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1.
The solution polymerization of acrylamide (AM) on cationic guar gum (CGG) under nitrogen atmosphere using ceric ammonium sulfate (CAS) as the initiator has been realized. The effects of monomer concentration and reaction temperature on grafting conversion, grafting ratio, and grafting efficiency (GE) have been studied. The optimal conditions such as 1.3 mol of AM monomer and 2.2 × 10?4 mol of CAS have been adopted to produce grafted copolymer (CGG1‐g‐PAM) of high GE of more than 95% at 10°C. The rates of polymerization (Rp) and rates of graft copolymerization (Rg) are enhanced with increase in temperature (<35°C).The Rp is enhanced from 0.43 × 10?4 mol L?1 s?1 for GG‐g‐PAM to 2.53 × 10?4 mol L?1 s?1 for CGG1‐g‐PAM (CGG1, degree of substitute (DS) = 0.007), and Rg from 0.42 × 10?4 to 2.00 × 10?4 mol L?1 s?1 at 10°C. The apparent activation energy is decreased from 32.27 kJ mol?1 for GG‐g‐PAM to 8.09 kJ mol?1 for CGG1‐g‐PAM, which indicates CGG has higher reactivity than unmodified GG ranging from 10 to 50°C. Increase of DS of CGG will lead to slow improvement of the polymerization rates and a hypothetical mechanism is put forward. The grafted copolymer has been characterized by infrared spectroscopy, thermal analysis, and scanning electron microscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3715–3722, 2007 相似文献
2.
Asad‐ur‐Rehman Saman Wijesekara R.G Nakao Nomura Seigo Sato Masatoshi Matsumura 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(7):1072-1080
BACKGROUND: The objective of the present work is to report an efficient pre‐treatment process for sunflower oil biodiesel raw glycerol (SOB‐RG) and its fermentation to 1,3‐propanediol. RESULTS: The growth inhibition percentages of Clostridium butyricum DSM 5431 on grade A (pH 4.0) and grade B (pH 5.0) phosphoric acid‐treated SOB‐RG were similar to those of pure glycerol at 20 g glycerol L?1; i.e., 18.5 ± 0.707% to 20.5 ± 0.7% inhibition. In grade A, growth inhibition was reduced from 85.25 ± 0.35% to 32 ± 1.4% (a 53.25% reduction) at 40 g glycerol L?1 by washing grade A raw glycerol twice with n‐hexanol (grade A‐2). The kinetic parameters for product formation and substrate consumption in anaerobic batch cultures gave almost similar values at 20 g glycerol L?1, while at 50 g glycerol L?1 volumetric productivity (Qp) and specific rate of 1,3‐propanediol formation (qp) were improved from 1.13 to 1.85 g L?1 h?1 and 1.60 to 2.65 g g?1 h?1, respectively, by employing grade A‐2 raw glycerol, while the yields were similar (0.5–0.52 g g?1). CONCLUSION: The results are important as the pre‐treatment of SOB‐RG is necessary to develop bioprocess technologies for conversion of SOB‐RG to 1,3‐propanediol. Copyright © 2008 Society of Chemical Industry 相似文献
3.
Ilgi Karapinar Kapdan Sebnem Aslan 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(7):998-1005
BACKGROUND: The aim of this study was to evaluate the ammonium nitrogen removal performance of algae culture Chlorella vulgaris in a novel immobilized photobioreactor system under different operating conditions and to determine the biokinetic coefficients using the Stover–Kincannon model. RESULTS: The photobioreactor was continuously operated at different initial ammonium nitrogen concentrations (NH4‐N0 = 10–48 mg L−1), hydraulic retention times (HRT = 1.7–5.5 days) and nitrogen/phosphorus ratios (N/P = 4/1–13/1). Effluent NH4‐N concentrations varied between 2.1 ± 0.5 mg L−1 and 26 ± 1.2 mg L−1 with increasing initial NH4‐N concentrations from 10 ± 0.6 mg L−1 to 48 ± 1.8 mg L−1 at θH = 2.7 days. The maximum removal efficiency was obtained as 79 ± 4.5% at 10 mg L−1 NH4‐N concentration. Operating the system for longer HRT improved the effluent quality, and the percentage removal increased from 35 ± 2.4% to 93 ± 0.2% for 20 mg L−1 initial NH4‐N concentration. The N/P ratio had a substantial effect on removal and the optimum ratio was determined as N/P = 8/1. Saturation value constant, and maximum substrate utilization rate constant of the Stover–Kincannon model for ammonium nitrogen removal by C. vulgaris were determined as KB = 10.3 mg L−1 d−1, Umax = 13.0 mg L−1 day−1, respectively. CONCLUSION: Results indicated that the algae‐immobilized photobioreactor system had an effective nitrogen removal capacity when the operating conditions were optimized. The optimal conditions for the immobilized photobioreactor system used in this study can be summarized as HRT = 5.5 days, N/P = 8 and NH4‐N0 = 20 mg L−1 initial nitrogen concentration to obtain removal efficiency greater than 90%. Copyright © 2008 Society of Chemical Industry 相似文献
4.
Hongjie Wang Ruiping Liu Jiuhui Qu Maohong Fan Huaizheng Li 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(7):966-971
BACKGROUND: Due to its strong colour, high concentrations of fluorides and chemical oxygen demand (CODCr) and large amount of suspended solids (SS), the waste‐water from carbon production (WCP) seriously affects the stability of the circulating system of Guizhou Branch, Aluminium Corporation of China. In this paper, the performance of a pilot‐scale (24 m3 d?1) combined treatment plant, consisting of chemical precipitation, coagulation, and Fenton oxidation, for the treatment of WCP was investigated. RESULTS: Lime precipitation and hydrated ferrous sulphate (HFS) coagulation, with polyacrylamide (PAM) as a coagulation aid, proved to be effective in the removal of colour (>70%), suspended solids (SS) (>90%) and fluoride (>80%) from the WCP. Subsequent Fenton oxidation combined with coagulation as a final treatment efficiently removed SS, F?, CODCr, dissolved organic carbon (DOC) and colour. The average total removal efficiencies of these parameters in the pilot‐scale combined technology were as follows: SS = 98.8%, F? = 95.7%, CODCr = 94.8%, DOC = 91.8% and colour = 98.3%, giving an average effluent quality: colour 24 (multiple), CODCr 168 mg L?1, DOC 80 mg L?1, F? 38 mg L?1 and SS 44 mg L?1, consistent with the reusable water limits for the process. CONCLUSIONS: The current experimental results and the economic evaluation suggest that the combined process could be advantageous and feasible for the treatment of WCP. Copyright © 2009 Society of Chemical Industry 相似文献
5.
Tonni Agustiono Kurniawan Lo Waihung Eveliina Repo Mika ET Sillanpää 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2010,85(12):1616-1627
BACKGROUND: At concentrations higher than 1 mg L?1, 4‐chlorophenol (4‐CP) is very toxic to living organisms, and if ingested beyond the permitted concentration it causes health disorders such as cancer and mutation. This laboratory study investigates treatment of contaminated water laden with 4‐CP using coconut shell charcoal (CSC) waste. Batch studies were conducted to study the effects of dose, pH, and equilibrium time on 4‐CP removal. To improve 4‐CP removal, surface modification of the adsorbent with TiO2, HNO3, and/or NaOH was undertaken. RESULTS: At an initial 4‐CP concentration of 25 mg L?1 under optimized conditions (dose 13.5 g L?1, pH 2.0; agitation speed 150 rpm and 50 min equilibrium time), the NaOH‐treated CSC demonstrated a greater removal of 4‐CP (71%) than those oxidized with HNO3 (40%) and/or coated with TiO2 (52%). The adsorption capacity of the NaOH‐treated CSC (54.65 mg g?1) was higher than those treated with HNO3 (23.13 mg g?1) or coated with TiO2 (48.42 mg g?1). CONCLUSION: Although treatment results using the NaOH‐treated CSC alone were promising, the treated effluents were still unable to meet the required limit of less than 1 mg L?1. Therefore, subsequent treatments are still required to complement the removal of 4‐CP from the wastewater. Copyright © 2010 Society of Chemical Industry 相似文献
6.
J Jegan Roy T Emilia Abraham 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2006,81(11):1836-1839
Cross‐linked enzyme crystals (CLEC) of laccase were prepared by crystallizing laccase with 75% (NH4)2SO4 and cross‐linking using 1.5% glutaraldehyde. The cross‐linked enzyme crystals were further coated with 1 mmol L?1 β‐cyclodextrin by lyophilization. The lyophilized enzyme crystals were used as such for the biotransformation of pyrogallol to purpurogallin in a packed‐bed reactor. The maximum conversion (76.28%) was obtained with 3 mmol L?1 pyrogallol at a residence time of 7.1 s. The maximum productivity (269.03 g L?1 h?1) of purpurogallin was obtained with 5 mmol L?1 pyrogallol at a residence time of 3.5 s. The productivity was found to be 261.14 g L?1 h?1 and 251.1 g L?1 h?1 when concentrations of 3 mmol L?1 and 7 mmol L?1 respectively were used. The reaction rate of purpurogallin synthesis was maximum (2241.94 mg purpurogallin mg?1 CLEC h?1) at a residence time of 3.5 s, when 5 mmol L?1 pyrogallol was used as the substrate. The catalyst to product ratio calculated for the present biotransformation was 1:2241. The CLEC laccase had very high stability in reuse and even after 650 h of continuous use, the enzyme did not lose its activity. Copyright © 2006 Society of Chemical Industry 相似文献
7.
Xinli Zhang Zhi Liu Jianjun Yi Haibing Huang Xiuli Dou Hongpeng Zhen Qigu Huang Kejing Gao Mingge Zhang Wantai Yang 《Polymer International》2013,62(3):419-426
Phthaldialdehyde and phthaldiketone were treated with substituted phenols of 2‐amino‐4‐methylphenol, 2‐amino‐5‐methylphenol and 2‐amino‐4‐t‐butylphenol, respectively, and then treated with transition metal halides of TiCl4, ZrCl4 and YCl3. A series of novel non‐metallocene catalysts (1–12) with phenoxy‐imine ligands was obtained. The structures and properties of the catalysts were characterized by 1H NMR and elemental analysis. The catalysts (1–12) were used to promote ethylene (co‐)polymerization after activation by methylaluminoxane. The effects of the structures and center atoms (Ti, Zr and Y) of these catalysts, polymerization temperature, Al/M (M = Ti, Zr and Y) molar ratio, concentration of the catalysts and solvents on the polymerization performance were investigated. The results showed that the catalysts were favorable for ethylene homopolymerization and copolymerization of ethylene with 1‐hexene. Catalyst 10 is most favorable for catalyzing ethylene homopolymerization and copolymerization of ethylene with 1‐hexene, with catalytic activity up to 2.93 × 106 gPE (mol Y)?1 h?1 for polyethylene (PE) and 2.96 × 106 gPE (mol Y)?1 h?1 for copolymerization of ethylene with 1‐hexene under the following conditions: polymerization temperature 50 °C, Al/Y molar ratio 300, concentration of catalyst 1.0 × 10?4 L?1 and toluene as solvent. The structures and properties of the polymers obtained were characterized by Fourier transform infrared spectroscopy, 13C NMR, wide‐angle X‐ray diffraction, gel permeation chromatography and DSC. The results indicated that the obtained PE catalyzed by 4 had the highest melting point of 134.8 °C and the highest weight‐average molecular weight of 7.48 × 105 g mol?1. The copolymer catalyzed by 4 had the highest incorporation of 1‐hexene, up to 5.26 mol%, into the copolymer chain. © 2012 Society of Chemical Industry 相似文献
8.
María Dolores Blanco Marta Benito Rosa Olmo César Teijón Elena Pérez Issa Katime José M Teijón 《Polymer International》2012,61(7):1202-1212
Copolymeric nanohydrogels based on N‐isopropylacrylamide, N‐(pyridin‐4‐ylmethyl)acrylamide and tert‐butyl‐2‐acrylamidoethyl carbamate, synthesized by microemulsion polymerization, were characterized using Fourier transform infrared spectroscopy and their size (38–52 nm) determined using quasielastic light scattering. Folic acid was covalently attached to the nanohydrogels (1.40 ± 0.07 mmol g?1). Tamoxifen (6.7 ± 0.2–7.3 ± 1.2 µg TMX mg?1 nanohydrogel), a hydrophobic anticancer drug, and 5‐fluorouracil (7.7 ± 0.7–10.14 ± 1.75 µg 5‐FU mg?1 nanohydrogel), a hydrophilic anticancer drug, were loaded into the nanohydrogels. Maximum in vitro TMX release (77–84% of loaded drug) depended on interactions of the drug with hydrophobic clusters of the nanogels; however, no nanogel/5‐FU interactions allowed total release of the loaded drug. The cytotoxicity of unloaded nanohydrogels in MCF7, T47D and HeLa cells was low. Cell uptake of nanogels without bound folic acid took place in the three cell types by unspecific internalization in a time‐dependent process. Cell uptake increased for folic acid‐targeted nanohydrogels in T47D and HeLa cells, which have folate receptors. The administration of 10 and 30 µmol L?1 TMX by TMX‐loaded nanogels and 10 µmol L?1 5‐FU by 5‐FU‐loaded nanogels was effective on the three cell types, and the best results were obtained for folic acid‐targeted nanohydrogels. Copyright © 2012 Society of Chemical Industry 相似文献
9.
Zhi‐Qing Zhao Li‐Li Xu Wen‐Bing Li Mei‐Zhen Wang Xiao‐Li Shen Gang‐Shuang Ma Dong‐Sheng Shen 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2012,87(10):1489-1496
BACKGROUND: The commercial use of organofluorine compounds has dramatically increased over the past few years. However, little information has been reported on the potential toxicity of organofluorine compounds to anaerobic digestion processes. In this work, the effects of 4‐fluorophenol (p‐FP), 4‐fluorobenzoic acid (p‐FB) and 4‐fluoroaniline (p‐FA) on methanogenesis and biodegradability were evaluated using sucrose‐fed systems. RESULTS: The anaerobic biodegradation of three test compounds was not observed in the study. Adsorption of p‐FP, p‐FB and p‐FA to the sludge fitted the linear model well (r2 > 0.94). The partition coefficient Kd was 25 L kg?1 for p‐FP, 16 L kg?1 for p‐FB and 26 L kg?1 for p‐FA. Both methanogensis and hydrolysis acidification were inhibited in the presence of three test compounds. The half maximal inhibitory concentrations (IC50s) of methanogenic activity were 339, 1390 and 1907 mg L?1 for p‐FP, p‐FB and p‐FA, respectively. A significant linear correlation (R2 = 0.99, P < 0.05) was obtained between the half maximal inhibitory concentrations and the most negative atomic charges of molecules (q?) of the three F‐substituent aromatics. CONCLUSIONS: Three F‐substituent aromatics had specific effects on methanogensis, hydrolysis acidification and syntrophic cooperation in anaerobic systems. Copyright © 2012 Society of Chemical Industry 相似文献
10.
Kwang V Lo Ping H Liao Gui Q Yin 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(10):1370-1374
BACKGROUND: Microwave‐enhanced advanced oxidation processes with and without the addition of ferrous sulfate (MW/H2O2/Fe2+‐AOP and MW/H2O2‐AOP respectively) were studied for reduction of solids and solubilisation of nutrients from secondary sewage sludge. RESULTS: For the MW/H2O2/Fe2+‐AOP the yields of solubilisation of orthophosphate and ammonia decreased with increasing temperature. The best results (88.1 mg L?1 for orthophosphate and 22.7 mg L?1 for ammonia) were obtained at a treatment temperature of 40 °C. In contrast, the MW/H2O2‐AOP had an advantage when it was operated at higher temperatures of 60 and 80 °C. The highest yields of solubilisation were obtained at 60 °C for orthophosphate (81.1 mg L?1) and at 80 °C for both ammonia (35.0 mg L?1) and soluble chemical oxygen demand (1954 mg L?1). Over the temperature range used in this study, the MW/H2O2‐AOP gave a better performance than the MW/H2O2/Fe2+‐AOP. CONCLUSION: For sewage sludge treatment the MW/H2O2‐AOP is more effective than the MW/H2O2/Fe2+‐AOP in terms of solid reduction and nutrient solubilisation. It will also be more cost‐effective, as it does not require iron addition in the process. Copyright © 2008 Society of Chemical Industry 相似文献
11.
B Kasapgil Ince A Selcuk O Ince 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2002,77(6):711-719
The performance of an upflow anaerobic filter (UAF) treating a chemical synthesis‐based pharmaceutical wastewater was evaluated under various operating conditions. During start‐up, the UAF was initially fed by glucose till an organic loading rate (OLR) of approximately 7.5 kg COD m?3 day?1 with a hydraulic retention time of 2.3 days. A soluble COD removal efficiency of 98% was achieved before the addition of the wastewater. Initially, the filter inertia was acclimatized to the wastewater by sequential feeding of 10% (w/v), 30% (w/v) and 70% (w/v) of the pre‐aerated wastewater mixed with glucose followed by a 100% (w/v) pre‐aerated wastewater. During the operation, the COD removal efficiency and methane yield decreased to 75% and 0.30 m3 CH4 kg?1 CODremoved respectively. As the UAF became accustomed to the pre‐aerated wastewater, raw wastewater was fed in increasing ratios of 20% (w/v), 60% (w/v) and 80% (w/v) with the pre‐aerated wastewater as the remaining part. During this stage of the operation, a COD removal efficiency in a range of 77–86% was achieved and the methane yield decreased to 0.24 m3 CH4 kg?1 CODremoved. Finally, 100% (w/v) raw wastewater was fed and a COD removal efficiency of 65% was achieved with a methane yield of 0.20 m3 CH4 kg?1 CODremoved. At the end of the operation, acetoclastic methanogenic activity was only measured in the bottom section of the UAF, this showed a 90% reduction in comparison with activity of inoculation sludge. Microscopic examinations revealed that rod‐shaped methanogens remained as the dominant species whereas Methanosarcina‐like species and filaments were present only in insignificant numbers along the UAF. © 2002 Society of Chemical Industry 相似文献
12.
Onur Ömer Söǧüt Mesut Akgün 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2010,85(5):640-647
BACKGROUND: Supercritical water oxidation (SCWO) of dyehouse waste‐water containing several organic pollutants has been studied. The removal of these organic components with unknown proportions is considered in terms of total organic carbon concentration (TOC), with an initial value of 856.9 mg L?1. Oxidation reactions were performed using diluted hydrogen peroxide. The reaction conditions ranged between temperatures of 400–600 °C and residence times of 8–16 s under 25 MPa of pressure. RESULTS: TOC removal efficiencies using SCWO and hydrothermal decomposition were between 92.0 and 100% and 6.6 and 93.8%, respectively. An overall reaction rate, which consists of hydrothermal decomposition and the oxidation reaction, was determined for the hydrothermal decomposition of the waste‐water with an activation energy of 104.12 ( ± 2.6) kJ mol?1 and a pre‐exponential factor of 1.59( ± 0.5) × 105 s?1. The oxidation reaction rate orders for the TOC and the oxidant were 1.169 ( ± 0.3) and 0.075 ( ± 0.04) with activation energies of 18.194 ( ± 1.09) kJ mol?1, and pre‐exponential factor of 5.181 ( ± 1.3) L0.244 mmol?0.244 s?1 at the 95% confidence level. CONCLUSION: Results demonstrate that the SCWO process decreased TOC content by up to 100% in residence times between 8 and 16 s under various reaction conditions. The treatment efficiency increased remarkably with increasing temperature and the presence of excess oxygen in the reaction medium. Color of the waste‐water was removed completely at temperatures of 450 °C and above. Copyright © 2010 Society of Chemical Industry 相似文献
13.
Multiobjective optimization of microalgae (Chlorella sp.) growth in a photobioreactor using Box‐Behnken design approach
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S. M. Zakir Hossain Abdullah Alnoaimi Shaikh A. Razzak Husny Ezuber Nader Al‐Bastaki Mohammed Safdar Salman Alkaabi Mohammad M. Hossain 《加拿大化工杂志》2018,96(9):1903-1910
14.
Emanuele Riscaldati Mauro Moresi Federico Federici Maurizio Petruccioli 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2002,77(9):1013-1024
Ammonium fumarate production from glucose‐based media by Rhizopus arrhizus NRRL 1526 with mycelial growth controlled by phosphorus limitation exhibited mixed‐growth‐associated product formation kinetics, with growth‐associated production related to secondary mycelial growth only. The contribution of the primary mycelial growth phase was minimised by resorting to prolonged batch production using free mycelia under intermittent glucose feeding or repeated batch production using immobilised mycelia. The metabolic activity of free or immobilised mycelia was limited by fumarate accumulation or by oxygen diffusion phenomena, respectively. For batch cultures in a 15 dm3 stirred bioreactor the peripheral impeller speed (vI) was increased from 1.88 to 3.3 m s?1, and the fumarate yield coefficient on glucose increased from 0.25 ± 0.01 to 0.42 ± 0.02 g g?1, while the malate yield coefficient on fumarate (YM/F) reduced from 0.46 ± 0.01 to 0.14 ± 0.01 g g?1. With a net increase in the fumarate‐to‐malate ratio from 2 to 6.5, a vI value of 3.3 m s?1 gave the best fermentation performance and provided a basis for further scale‐up studies. © 2002 Society of Chemical Industry 相似文献
15.
Orhan Ince Bahar Kasapgil Ince Orhan Yenigun 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2001,76(6):573-578
A 450 dm3 pilot‐scale upflow anaerobic sludge blanket (UASB) reactor was used for the treatment of a fermentation‐based pharmaceutical wastewater. The UASB reactor performed well up to an organic loading rate (OLR) of 10.7 kg COD m?3 d?1 at which point 94% COD removal efficiency was achieved. This high treatment efficiency did not continue, however and the UASB reactor was then operated at lower OLRs for the remainder of the study. Specific methanogenic activity (SMA) tests were, therefore, carried out to determine the potential loading capacity of the UASB reactor. For this purpose, the SMA tests were carried out at four different initial acetate concentrations, namely 500 mg dm?3, 1000 mg dm?3, 1500 mg dm?3 and 2000 mg dm?3 so that substrate limitation could not occur. The results showed that the sludge sample taken from the UASB reactor (OLR of 6.1 kg COD m?3 d?1) had a potential acetoclastic methane production (PMP) rate of 72 cm3 CH4 g?1 VSS d?1. When the PMP rate was compared with the actual methane production rate (AMP) of 67 cm3 CH4 g?1 VSS d?1 obtained from the UASB reactor, the AMP/PMP ratio was found to be 0.94 which ensured that the UASB reactor was operated using its maximum potential acetoclastic methanogenic capacity. In order to achieve higher OLRs with desired COD removal efficiencies it was recommended that the UASB reactor should be loaded with suitable OLRs pre‐determined by SMA tests. © 2001 Society of Chemical Industry 相似文献
16.
Study on preparation and properties of PVA‐SA‐PHB‐AC composite carrier for microorganism immobilization
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Polyvinyl alcohol(PVA) bead crosslinked with boric acid has been widely utilized as a microorganism immobilization carrier. However, it has some disadvantages such as drastic cell viability loss, small adsorption capacity and mass transfer limitation. To improve upon these drawbacks, a new method to prepare PVA composite pieces with the addition of activated carbon (AC) and poly‐3‐hydroxybutyrate(PHB) was explored through a combination of freezing/thawing and the boric acid method and by using Tween‐80 to improve the mass transfer performance of hydrophobic organics. m‐Cresol and pyrene were used as representative compounds with benzene ring structures to model hydrophilic and hydrophobic organics in order to test the performance of PVA pieces. The results showed that, compared with the boric acid method alone, a combination of freezing/thawing and the boric acid method led to a decrease in total organic carbon(TOC) loss from 0.315 g g?1 to 0.033 g g?1 and increased the oxygen uptake rate(OUR) of microorganisms from 0.03 mg L?1·min?1 to 0.22 mg L?1 min?1. The m‐cresol equilibrium adsorption amount of the PVA‐SA(sodium alginate)‐PHB‐AC piece was 2.80 times that of the PVA‐SA piece. The diffusion coefficient of pyrene in the PVA‐SA‐PHB‐AC piece increased from 0.53×10?9 m2 min?1 to 2.30×10?9 m2 min?1 with increasing concentrations of Tween‐80 from 1000 mg L?1 to 5000 mg L?1. The PVA‐SA‐PHB‐AC composite carrier demonstrated great scope for immobilizing microorganisms for practical wastewater bio‐treatment. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39837. 相似文献
17.
Jin‐Hong Fan Hong‐Wu Wang De‐Li Wu Lu‐Ming Ma 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2010,85(8):1117-1121
BACKGROUND: Dinitrotoluenes (DNTs) are environmentally persistent, making the remediation of contaminated streams and groundwater difficult. Zero‐valent iron (Fe0) can be used as an electron source for the reduction of recalcitrant DNTs in waste‐water and thus enhance their biodegradability. However, little is known about the qualitative effects of major anions and cations present in waste‐water on the reduction of DNTs by Fe0. RESULTS: The presence of Na2SO4 and NaCl at levels between 0.25 and 2 mmol L?1 was observed to enhance the reactivity of Fe0 towards 2,4‐DNT. The positive effect of K2SO4 is stronger than that of Na2SO4 at the same level (1 mmol L?1). Varying (NH4)2SO4 from 0.1 to 1.0 mmol L?1 improved the efficiency of 2,4‐DNT degradation by Fe0. The effects of varying NaNO3 and NaNO2 from 0 mmol L?1 to 4.7 mmol L?1 and 0 mmol L?1 to 5.8 mmol L?1, respectively, were also investigated. Both NaNO3 and NaNO2 at low concentration improved the efficiency of 2,4‐DNT degradation by Fe0, however, at high concentration, inhibiting effects appeared. CONCLUSION: SO42?, Cl?, Na+, K+ and NH4+ notably enhanced 2,4‐DNT reduction by Fe0 at the tested concentrations. The positive effect of K+, Cl? was relatively stronger than that of Na+ and sulfate (SO42?). However, the effect of NH4+ was relatively weaker at concentrations greater than 1.0 mmol L?1. The presence of low concentrations of NO3? and NO2? promoted 2,4‐DNT reduction by Fe0 and inhibited the reaction. The results suggest that 2,4‐DNT reduction by Fe0 can be controlled by the ions composition of the waste‐water. Copyright © 2010 Society of Chemical Industry 相似文献
18.
Ana Lucía Morocho Jácome Attilio Converti Sunao Sato João Carlos Monteiro de Carvalho 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2012,87(11):1574-1583
BACKGROUND: Fed‐batch culture allows the cultivation of Arthrospira platensis using urea as nitrogen source. Tubular photobioreactors substantially increase cell growth, but the successful use of this cheap nitrogen source requires a knowledge of the kinetic and thermodynamic parameters of the process. This work aims at identifying the effect of two independent variables, temperature (T) and urea daily molar flow‐rate (U), on cell growth, biomass composition and thermodynamic parameters involved in this photosynthetic cultivation. RESULTS: The optimal values obtained were T = 32 °C and U = 1.16 mmol L?1 d?1, under which the maximum cell concentration was 4186 ± 39 mg L?1, cell productivity 541 ± 5 mg L?1 d?1 and yield of biomass on nitrogen 14.3 ± 0.1 mg mg?1. Applying an Arrhenius‐type approach, the thermodynamic parameters of growth (ΔH* = 98.2 kJ mol?1; ΔS* = ? 0.020 kJ mol?1 K?1; ΔG* = 104.1 kJ mol?1) and its thermal inactivation ( kJ mol?1; kJ mol?1 K?1; kJ mol?1) were estimated. CONCLUSIONS: To maximize cell growth T and U were simultaneously optimized. Biomass lipid content was not influenced by the experimental conditions, while protein content was dependent on both independent variables. Using urea as nitrogen source prevented the inhibitory effect already observed with ammonium salts. Copyright © 2012 Society of Chemical Industry 相似文献
19.
Xiao Ling Yong‐You Hu Chun‐De Wu Gui‐Ping Hu 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2006,81(2):128-135
The performance of the hydrolyzation film bed and biological aerated filter (HFB–BAF) combined system in pilot scale (with a daily treatment quantity of 600–1300 m3 d?1), operated for 234 days, for low‐strength domestic sewage was assessed using different amounts of aeration, reflux ratios and hydraulic loading rates (HLR). In steady state it was found that the average removal efficiency of chemical oxygen demand (COD) and biological oxygen demand at 5 days (BOD5) were 82.0% and 82.2% and the average effluent concentrations were 15.8 mg L?1 and 9.4 mg L?1 respectively as the HFB was running at an HLR of 1.25–1.77 m3 m?2 h?1 and the BAF was running at an HLR of 1.56–2.21 m3 m?2 h?1. In general, the removal efficiency of total nitrogen (TN) fluctuated with the HLR, gas–water ratio and reflux ratio, so the ratio of gas to water should be controlled from 2:1 to 3:1 and the reflux ratio should be as high as possible. The effluent concentration of TN was 10.4 mg L?1 and the TN removal averaged 34.3% when the gas–water ratio was greater than 3:1 and the reflux ratio was 0.5. The effluent concentration and removal efficiency of NH4+‐N averaged respectively 2.3 mg L?1 and 78.5%. The overall reduction of total phosphorus (TP) was 30% and the average effluent concentration was 0.95 mg L?1. The removal efficiency of linear alkylbenzene sulfonates (LAS) reached 83.8% and the average effluent concentration was almost 0.9 mg L?1. The effluent concentration and removal efficiency of polychlorinated biphenyls (PCBs) were 0.0654 µ g L?1 and 37.05% respectively when the influent concentration was 0.1039 µ g L?1. The excess sludge containing water (volume 15 m3) was discharged once every 3 months. The power consumption of aeration was 0.06–0.09 kWh of sewage treated. The results show that the HFB–BAF combined technology is suitable for the treatment of low‐concentration municipal sewage in south China. Copyright © 2005 Society of Chemical Industry 相似文献
20.
Prabir Ghosh Chandra Kumar Amar Nath Samanta Subhabrata Ray 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2012,87(7):914-923
BACKGROUND: Heterogeneous Fenton catalysts have been used to treat various organic pollutants in an aqueous environment. The present study has investigated the degradation of 2,4‐dinitrophenol (2,4‐DNP), a priority pollutant generated by such industries as pharmaceuticals, pesticides, pigments and dyes. Degradation of 2,4‐DNP (100 mg L?1) was studied using Fe3+ loaded on Al2O3 as a heterogeneous catalyst in the presence of H2O2, and the efficiency compared with the homogeneous Fe3+/H2O2 based Fenton‐like process. The effect of different parameters for both processes, such as catalyst loading, H2O2 concentration, initial solution pH, initial substrate concentration and temperature were investigated and the optimum operating conditions determined. RESULTS: Under optimal operating conditions of the homogeneous system ([Fe3+] 125 mg L?1; [H2O2] 250 mg L?1; pH 3; room temperature), 92.5% degradation was achieved in 35 min for an initial 2,4‐DNP concentration of 100 mg L?1. In the case of immobilized Fe (Fe3+–Al2O3 catalyst), degradation improved to 98.7% under the condition 10 wt% [Fe3+–Al2O3] 1 g L?1 catalyst loading; [H2O2] 250 mg L?1; pH 3; at room temperature for the same duration. CONCLUSIONS: This study demonstrated the stability and reusability of the prepared heterogeneous catalyst. This process is a viable technique for treatment of aqueous solutions containing contaminants. Copyright © 2012 Society of Chemical Industry 相似文献